PROJECT SUMMARY This is a competing renewal application for a highly successful T32 program that has trained more than 180 predoctoral students in toxicology/environmental health sciences (EHS) over the last 45 years. The objective of this predoctoral program is to train the next generation of environmental health scientists through interdisciplinary research and coursework that address issues of direct relevance to the NIEHS mission. We are requesting 2 years of support for each of 8 predoctoral trainees beginning after their first or second year in a PhD degree program. Trainees are recruited from several UC Davis graduate programs that provide disciplinary training relevant to EHS, including toxicology, cell and molecular biology, exposure assessment, epidemiology, neuroscience, immunology and genetics. Training faculty ? 32 active researchers from 19 departments ? have substantial experience mentoring predoctoral students. Faculty research focuses on mechanisms by which environmental factors contribute to human disease and encompasses diverse areas within EHS, including respiratory toxicology, cancer, neurotoxicology, genotoxicity, epigenetics, and metabolic disorders. Significant interactions between training faculty members promote interdisciplinary approaches to EHS research. Trainees have access to advanced technologies, such as proteomics, epi/genomics and metabolomics, state-of-the-art imaging, genetically modified organisms, and inhalation facilities for rodents and non-human primates. A strength of EHS research at UC Davis is the vertical integration of studies directed toward understanding environmentally induced disease. Molecular, cellular, tissue, and diverse animal models, including nonhuman primate models, complement human clinical samples obtained through the UC Davis Clinical and Translational Science Center (CTSC) and epidemiologic studies. The training program leverages the activities and resources of multiple research centers at UC Davis to provide synergy and promote connections to disease prevention and public health; examples include the NIEHS P30 Environmental Health Sciences Core Center at UC Davis, the MIND Institute, Center for Children's Environmental Health, NCI Comprehensive Cancer Center, Western Center for Agricultural Health and Safety, NIEHS Superfund Program and the NIEHS Center for Nanotechnology Health Implications Research. The training program emphasizes practical instruction in scientific writing and communication of scientific findings to peers and lay audiences through chalk talks, annual retreats, town halls, and national meetings. Trainees are also exposed to emerging concepts, controversies, and technologies in environmental health by participating in a trainee-organized and -managed seminar series that hosts leading environmental health scientists from across the country, as well as through faculty?student interactions during a summer course in which trainees explore a current issue relevant to environmental health under the guidance of training faculty. Trainees will receive training in responsible conduct of research. The training program builds on an excellent track record of training leaders in EHS in academia, government, and the private sector.